package org.apache.maven.settings.merge;

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.apache.maven.settings.IdentifiableBase;
import org.apache.maven.settings.Settings;
import org.codehaus.plexus.util.StringUtils;

/**
 * @author <a href="mailto:vincent.siveton@gmail.com">Vincent Siveton</a>
 * @author Benjamin Bentmann
 */
public class MavenSettingsMerger {

  /**
   * @param dominant
   * @param recessive
   * @param recessiveSourceLevel
   */
  public void merge(Settings dominant, Settings recessive, String recessiveSourceLevel) {
    if (dominant == null || recessive == null) {
      return;
    }

    recessive.setSourceLevel(recessiveSourceLevel);

    List<String> dominantActiveProfiles = dominant.getActiveProfiles();
    List<String> recessiveActiveProfiles = recessive.getActiveProfiles();

    if (recessiveActiveProfiles != null) {
      if (dominantActiveProfiles == null) {
        dominantActiveProfiles = new ArrayList<String>();
        dominant.setActiveProfiles(dominantActiveProfiles);
      }

      for (String profileId : recessiveActiveProfiles) {
        if (!dominantActiveProfiles.contains(profileId)) {
          dominantActiveProfiles.add(profileId);
        }
      }
    }

    List<String> dominantPluginGroupIds = dominant.getPluginGroups();

    List<String> recessivePluginGroupIds = recessive.getPluginGroups();

    if (recessivePluginGroupIds != null) {
      if (dominantPluginGroupIds == null) {
        dominantPluginGroupIds = new ArrayList<String>();
        dominant.setPluginGroups(dominantPluginGroupIds);
      }

      for (String pluginGroupId : recessivePluginGroupIds) {
        if (!dominantPluginGroupIds.contains(pluginGroupId)) {
          dominantPluginGroupIds.add(pluginGroupId);
        }
      }
    }

    if (StringUtils.isEmpty(dominant.getLocalRepository())) {
      dominant.setLocalRepository(recessive.getLocalRepository());
    }

    shallowMergeById(dominant.getMirrors(), recessive.getMirrors(), recessiveSourceLevel);
    shallowMergeById(dominant.getServers(), recessive.getServers(), recessiveSourceLevel);
    shallowMergeById(dominant.getProxies(), recessive.getProxies(), recessiveSourceLevel);
    shallowMergeById(dominant.getProfiles(), recessive.getProfiles(), recessiveSourceLevel);

  }

  /**
   * @param dominant
   * @param recessive
   * @param recessiveSourceLevel
   */
  private static <T extends IdentifiableBase> void shallowMergeById(List<T> dominant, List<T> recessive,
      String recessiveSourceLevel) {
    Map<String, T> dominantById = mapById(dominant);

    for (T identifiable : recessive) {
      if (!dominantById.containsKey(identifiable.getId())) {
        identifiable.setSourceLevel(recessiveSourceLevel);

        dominant.add(identifiable);
      }
    }
  }

  /**
   * @param identifiables
   * @return a map
   */
  private static <T extends IdentifiableBase> Map<String, T> mapById(List<T> identifiables) {
    Map<String, T> byId = new HashMap<String, T>();

    for (T identifiable : identifiables) {
      byId.put(identifiable.getId(), identifiable);
    }

    return byId;
  }

}
